See also

*-*-*-*-*-*-*-*-*-*-*The F O R M U L A class*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*-* =========================
*-*
*-* This class has been implemented by Nicolas Brun (age 18).
*-* ========================================================
/*
*/
*-*
*-* Example of valid expressions:
*-* - sin(x)/x
*-* - [0]*sin(x) + [1]*exp(-[2]*x)
*-* - x + y**2
*-* - x^2 + y^2
*-* - [0]*pow([1],4)
*-* - 2*pi*sqrt(x/y)
*-* - gaus(0)*expo(3) + ypol3(5)*x
*-*
*-* In the last example above:
*-* gaus(0) is a substitute for [0]*exp(-0.5*((x-[1])/[2])**2)
*-* and (0) means start numbering parameters at 0
*-* expo(3) is a substitute for exp([3]+[4])*x)
*-* pol3(5) is a substitute for par[5]+par[6]*x+par[7]*x**2+par[8]*x**3
*-* (here Pol3 stands for Polynomial of degree 3)
*-*
*-* Comparisons operators are also supported (&&, ||, ==, <=, >=, !)
*-* Examples:
*-* sin(x*(x<0.5 || x>1))
*-* If the result of a comparison is TRUE, the result is 1, otherwise 0.
*-*
*-* Already predefined names can be given. For example, if the formula
*-* TFormula old(sin(x*(x<0.5 || x>1))) one can assign a name to the formula. By default
*-* the name of the object = title = formula itself.
*-* old.SetName("old").
*-* then, old can be reused in a new expression.
*-* TFormula new("x*old") is equivalent to:
*-* TFormula new("x*sin(x*(x<0.5 || x>1))")
*-*
*-* Up to 3 dimensions are supported (indicated by x, y, z)
*-* An expression may have 0 parameters or a list of parameters
*-* indicated by the sequence [par_number]
*-*
*-* A graph showing the logic to compile and analyze a formula
*-* is shown in TFormula::Compile and TFormula::Analyze.
*-* Once a formula has been compiled, it can be evaluated for a given
*-* set of parameters. see graph in TFormula::EvalPar.
*-*
*-* This class is the base class for the function classes TF1,TF2 and TF3.
*-* It is also used by the ntuple selection mechanism TNtupleFormula.
*-*
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

*-*-*-*-*-*Return address of string corresponding to special code*-*-*-*-*-*
*-* ======================================================
*-*
*-* This member function is inactive in the TFormula class.
*-* It may be redefined in derived classes.
*-*
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

*-*-*-*-*-*Return value corresponding to special code*-*-*-*-*-*-*-*-*
*-* ==========================================
*-*
*-* This member function is inactive in the TFormula class.
*-* It may be redefined in derived classes.
*-*
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

*-*-*-*-*-*Check if expression is in the list of defined variables*-*-*-*-*
*-* =======================================================
*-*
*-* This member function can be overloaded in derived classes
*-*
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

*-*-*-*-*-*-*-*-*-*-*Evaluate this formula*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*-* =====================
*-*
*-* The current value of variables x,y,z is passed through x, y and z.
*-* The parameters used will be the ones in the array params if params is given
*-* otherwise parameters will be taken from the stored data members fParams
*-*
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

*-*-*-*-*-*-*-*-*-*-*Evaluate this formula*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*-* =====================
*-*
*-* The current value of variables x,y,z is passed through the pointer x.
*-* The parameters used will be the ones in the array params if params is given
*-* otherwise parameters will be taken from the stored data members fParams
/*
*/
*-*
*-*
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

This page has been automatically generated. If you have any comments or suggestions about the page layout send a mail to ROOT support, or contact the developers with any questions or problems regarding ROOT.